


Absolute Zero

by hitori10



Series: For the glory of Mankind [1]
Category: Shingeki no Kyojin | Attack on Titan
Genre: Advanced Technology, Alternate Universe - Canon Divergence, Alternate Universe - Time Travel, Angst, Anxiety Attacks, Child Abandonment, Eren Yeager Has Heterochromia Iridum, Eventual Happy Ending, Eventual Levi/Eren Yeager, Eventual Romance, Eventual Smut, F/F, F/M, M/M, Mentions of Character Death, Night Terrors, Post-Traumatic Stress Disorder - PTSD, Tragedy
Language: English
Status: In-Progress
Published: 2019-03-03
Updated: 2019-03-02
Packaged: 2019-11-08 10:23:23
Rating: Mature
Warnings: Major Character Death
Chapters: 1
Words: 3,397
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17979530
Author URL: https://archiveofourown.org/users/hitori10/pseuds/hitori10
Summary: Time travel.It's something that's been spoken of within the science world; but has never proven to be a possibility. Such a feat is too great for human use.Yes, there is talk of multiple world lines existing at once, and how they all differ from one another, however, no one can prove their existence.No one has ever traveled through time and given concrete information that it is something that can be attained to save their god forsaken world.Fortunately or unfortunately for them, someone was about to find out just how wrong time travel really was.





	Absolute Zero

**Author's Note:**

> Lemme be honest here, this was completely inspired by me playing too much Steins Gate, and then this happened.

Absolute Zero

Chapter 1

* * *

Time travel.

It's something that's been spoken of within the science world; but has never proven to be a possibility. Such a feat is too great for human use.

Yes, there is talk of multiple world lines existing at once, and how they all differ from one another, however, no one can prove their existence.

No one has ever traveled through time and given concrete information that it is something that can be attained to save their god forsaken world.

Fortunately or unfortunately for them, someone was about to find out just how wrong time travel really was.

* * *

**Year**   **2050.**

A young man stood outside of his home in the middle of a cold winter's night; snowflakes settled into his brunet hair, leaving dew behind in it's wake.

His warm breath creating white mist before disappearing once more.

Bringing his coat closer to himself, he listened to the quiet of his small city. He savored these small moments since he learned their peace would come to an end if something didn't happen to prevent their inevitable end just a little more.

"You'll catch cold if you stay out here any longer."

He turned around at the sound of a woman's voice; his adoptive mother.

The woman's auburn hair was tied into a messy ponytail, her once white lab coat dwarfing her tired figure, her left eye absent of it's usual eye patch showing the fogginess of her once brilliant brown eye.

Turning back towards the scenery, he watched as some buildings lights turned out and the usual guards roamed the rooftops for their night watch while others slept until the sun rose; or late morning if the nightmares woke them up first.

"I'll go in a few minutes."

His mother watched him for some seconds before coming and standing beside him, arms hugging herself to keep warm.

"It's a lot colder than we predicted this winter. I wonder if that will hinder our experiments?" Her left fingers came up to cradle her chin in thought, quickly returning to it's previous spot to create warmth.

He shrugged, not sure what to say to that. His mother was the scientist here, not him. He was merely a solider fighting in a lost cause.

"Eren, I heard your last operation had moderate results."

The young man, Eren, nodded, "Yeah. Some useful information came back and that might help speed up your invention progress."

His mother, whose name was Hange Zoe, placed a hand on his right arm and led him back inside, where it was slightly warmer.

Both walked in silence as they made their way to the basement, where his mother's laboratory was located.

Eren had to take off his jacket upon entering, it was always to stuffy in here. Perhaps that's why his mother loved spending the cold months in here; during the summer though, it was pure hell.

Hange set down a cup of coffee in front of her exhausted son, nursing her own cup as she down across from him. "I heard we have a few more weeks before we have to evacuate on emergency."

The brunet took a drink from his cup, the bitter beverage soothing his sore throat, "Yeah, the commander is already getting in touch with other bases to create a safe haven for us. I was going to bring this up with the head of the city in the morning."

His mother slowly nodded, her grip tightening around her mug. "Have you been fighting safely against those monsters?"

"There's no such thing as fighting safely. If I do that, someone dies and I risk dying myself." Such was the mentality one needed to adopt when joining their cause.

"I see..."

It was quiet for some time; the only sound being the constant beeping of his mother's machine's needed for inventions.

When he was eighteen years old, Eren had decided to join the rebellion against the monsters that threatened to end humanity, and now five years later, his mother was still opposed to his decision.

He used to be so angry back then, at what? He really can't remember. He happens to be a bit emotionally detached now because of his experiences.

The fire that used to be in his green and golden eyes have dulled.

Looking at the somber and sunken figure of her son, Hanji knew this fight was quickly draining him of all will to live.

She knew how tough it was to go out there for days, even weeks at a time, and fight those horrifying things. More so when they came back with the corpses of their fallen comrades.

Often coming empty handed and only telling how their comrade lost their life because their body was used as a distraction to escape from certain death.

Hanji would sometimes find herself gazing into her son's differently colored eyes and remember the people that brought him into the world.

The once vivid green had been from his mother; a woman who loved her life and her son. But met a cruel end when a former solider threw her to her death to save his own miserable life because he was too much of a coward.

Gold having come from his father. She remembers seeing the knowledge reflecting from them when she met him. The man had been a spectacular scientist and a small beacon of hope towards a brighter future as a fellow colleague, but that image was quickly shattered with how she found her son.

Grisha had left his son abandoned in their old house when those monsters came to attack. He gladly fed his son to the wolves while he fled; claiming he had much to do in his life, and if he had to give up Eren, then so be it.

A piece of roofing had gone into the infants eye, leaving him screaming from immense pain. While they were able to save his eye, he was still partially blind in it.

The brunet knew the fate of his mother and the immense distaste he carried against his father now.

When he was out on missions, he wore an eye patch over his golden eye, leaving his right side to be his dominant one.

Hanji wished there was more that she could do for him, protect him more, but he was a rapidly growing man. She sometimes had trouble seeing the happy child he once was.

The child that used to come into her lab and ask all those exciting questions about experiments his mother was conducting.

Now before her, was a stone faced young man with so much trauma.

She can only brace herself for the anger that would come from him when she spoke next.

"The invention that I'm working on now is a time machine. It should be done by next week if all goes well."

Hanji looked down at the cooling coffee in her mug, waiting for the young man to blow up and curse up a storm...but it never came.

Instead, he looked stoic as ever. "What do you plan to do with it?"

"I was planning on picking someone to send back to the time 800 and possibly prevent this whole mess from occurring."

"But it's more complicated than that, isn't it?" He casually brought up his coffee and took a sip, almost like this topic wasn't a sensitive subject for him.

Hanji nodded, "Much could go wrong. The person we send back has to be prepared to fight tooth and nail to ensure this future doesn't happen."

"What happens if they succeed?"

"Then this timeline will be erased from existence."

Eren merely hummed, making a gesture with his hand letting his mother continue.

If there was one person who could let her ramble and not get annoyed, it was him.

"As you know, there are many timelines and each one is a result of something done because of the past. I think our world is because something went horribly wrong back in the year 800. With our time machine, not only would we be sending someone back, they would also enter another timeline and rewrite the past and create a new future."

Hanji got up and went to her desk, grabbing her notes and going back over to her son, who was still sitting comfortably, and flipped to a specific page before showing him.

The brunet leaned over, letting his eyes take in all the information that was written there.

"And we are also giving them specific instructions based on what they should do once they arrive."

"What are those instructions?"

Hanji was amazed; her son hadn't shown interest in these kind of things in years, "We have them join the Survey corps and gain their trust. There was a failed mission they went on once, to capture a criminal in the underground city and have him join the military. It took them five years, and around that time, titan activity increased."

She flipped to another page, "There was also a titan shifter, Eren Yeager, that helped in the military, but he was killed off once his powers were discovered."

"However," She pointed to a highlighted part at the bottom, "Rico found a textbook that said something different. Levi Ackerman, the criminal I mentioned, was never caught, and the military slowly fell apart. Eren Yeager lived a bit longer this time around, but he died in the fight against the female titan."

The brunet nodded slowly, "So, the whole point of this mission, is to send someone back to the past and prevent these two from dying and possibly changing our world?"

"That's the idea."

"Who do you have in mind for the candidate?"

"We're thinking someone from the rebellion."

He slowly circled the rim of his mug with his pointer finger, "But there's something I don't get."

"What's that?"

"How can these books exist when they have two forms of information based on what happened?"

Hanji shrugged, "I'm not sure, Rico and I are trying to figure that out ourselves. I've sent her to look more into the libraries we have here. We've also sent a request to the other towns to look for textbooks similar to the ones we found."

The brunet nodded, going back to his silence, signaling it was the end of their conversation.

His adoptive mother stayed with him for a while longer before saying she was tired and left him to his own devices, advising him not to stay up late.

Eren sat in his place for a few minutes before he got up and went to check on the time machine his mother was in the process of building.

It slipped his mind, but, they stumbled across an abandoned town a day away from their current location and inside he found nearly brand new equipment his mother could find some use for. He would have to tell her in the morning when she was more rested.

Towards the back of her laboratory was the invention itself; the time machine.

It was rather tall and so many machines were attached to it, monitoring any small change in it's creation.

A table was next to it with several computers showing different information, some notes and required parts to continue it's production.

His mother's writing, which looked more like chicken scratch, solid proof she hasn't been sleeping, was all over the papers that dominated any empty space that was left.

Letting his hand run over the blue prints next to one of her computers made a mixture of emotions run through him.

He'd heard from Rico some odd years ago, that his bastard of an old man was also making a time machine, but for more selfish reasons.

Apparently, he was trying to send himself or someone back in time and collect the titan serum that supposedly existed back then, inject someone with it from this world line, and try to prevent their end.

Rico theorized making the decision would only speed up their end.

Titans were so unpredictable now.

Every time he went out on a mission with the rebellion, he reported titan movement to Rico. She was both a strategist and scientist at heart.

They behaved nothing like the books suggested they did.

It was almost like someone was controlling them; they seemed so eerily intelligent.

Eren could count the amount of times where he felt uneasy around those monsters now that he was older and a captain.

The brunet always confided in his guardian seeing as he didn't have friends he could call his own.

His experiences made him...rather awkward in social settings.

Eren went over to the machine once more and placed his hand on the cool metal door.

If this thing truly have the power his mother was working towards, then maybe...

* * *

Come morning, the young captain had arranged for the head of the city to come to his mother's home and discuss information he had gained regarding how long they had before they had to leave.

The older man in front of him was named Braun, a tall, muscled man who was able to remain calm even in the most dire of consequences; he inherited the responsibilities he had now when his own father had passed away some years ago.

Handing the other the folder his commanding officer gave him, Eren spoke while Braun scanned through the papers, "The recent mission we went on did prove to be of some use. We have noticed less active movement towards the east, which struck us as off, so we sent others to investigate for us. Upon their arrival, they reported titans seemed to be...more frail."

Braun looked up from the papers, his brows furrowed, "How is that?"

"Apparently the constantly changing climate seems to have some effect on them, and it's also an area we haven't explored ourselves yet. The solders who went reported a severe lack of human activity and there were also no signs of electricity running through there."

It was written in a journal about a decade ago, if Eren can recall properly, a former commander had come to the conclusion that titans were attracted to electricity, and later confirmed such a theory when they cut open a titan and found a machine in them that made them run towards large amounts of electrical currents.

"What does the land look like?"

Eren pulled out a military issued phone, which was considered a luxury in their time and only given to the rebellion, he scrolled through photos for a moment before stopping.

He gave the phone to the older man; the photo showing a mountain area, full of lush green trees, running streams of clear water, and fortunately very little signs of civilization having come through there. "Please swipe to the right."

Braun did as he was told and his brown eyes widened.

It was the same photo taken from a different angle, but it showed a completely different climate right next to the warm area where the mountains stood. Next to the vibrant green grass were feet of snow, other trees with their branches frozen and lakes completely frozen over.

"One more if you would."

The last picture left the man stunned.

No more snow, frozen lakes, green grass and clear water. Instead in it's place, was a desert.

"How the hell is this possible?"

Eren shrugged, "I'm not sure myself. We have some scientists who assist the rebellion looking into the situation. But so far, they have no answer how this can even exist."

Braun still had a pensive look on his face as he handed the files back, "I assume you all think this is a possible safe haven for us."

"Looks that way. But the commander gave us orders to have this place investigated before issuing a city wide move there. We don't know the full details of why there is such a drastic weather change, he hopes we can have a better understanding within two weeks time."

The man crossed his arms, leaning forward slightly, "And how much time do we have left before we absolutely have to leave?"

"We have sixteen weeks before the situation becomes too dangerous for us to remain here anymore."

Braun nodded, standing up along with the young captain as they shook hands. "Keep me informed on anything important that happens."

"Of course, sir."

Eren showed him towards the door and ordered some other soldiers to accompany him home.

* * *

"Ren."

The brunet looked up from his documents to see his guardian, Rico, enter the room. "Do you need something?"

She nodded, closing the door and walking over to him. She tucked a strand of white hair behind her ear as she looked down at him, "Your mother said you had some important information to give me."

"Yeah, give me a minute."

Eren got up and went towards his filing cabinet, carefully looking for the documents he made just for Rico.

Once he got them, he handed them to her, inviting her to take a seat so they could talk when she was finished reading.

It took about forty five minutes before the woman spoke, "I was afraid my theory was right."

The theory that she was referring to seemed impossible, but within time and the necessary pieces, it wasn't so absurd anymore.

A group of people were monitoring the titans movement, and even creating some of them.

This rang to be true when the rebellion managed to capture a living titan and cut into it for further investigation and inside they discovered technology scientists were barely able to understand.

Eren had been holding off on giving her this because he wasn't sure what the scientists were able to find out. Nearly a year later, they came to this conclusion.

Having led one of their biggest missions, they used the tracking devices within the titans and find one of the headquarters. They raided the entire building and only brought back five of their creators, killing everyone else and effectively shutting down the entire building.

The brunet hummed, his face indifferent as he turned and faced Rico, "Look at the final page and see what name sticks out to you."

Rico felt uncomfortable with the tone his voice took, almost like it was empty, yet wanting to be angry at the same time.

Swallowing hard, she did as he asked and nearly dropped the stack of papers in shock.

**Head of creation doctor Grisha Jeager; the father of titans.**

She felt bile rise up in her throat, her own hand coming up and cupping over her mouth, harsh puffs of breath slipping passed her fingers.

Back when she was still within her teen years, Rico had the pleasure of meeting doctor Jeager.

He was a respectable man and an idol in her eyes.

But when they took Eren in when she was in her early twenties, the image began to blur.

And now,  _it was completely shattered._

"Oh Ren." She let out a soft sob when she finally calmed down and embraced the young man, his face buried in her shoulder, his own bare arms coming to wrap themselves around her waist.

As she placed her face into his brunet hair, Rico couldn't help but notice she was the only one crying.

* * *

Later that evening, Hanji, Eren and Rico were in his mother's laboratory.

The young captain had informed his mother about their recent find of materials he thought would be beneficial to her time machine, and now the two woman were reviewing photos that Eren had received some hours prior.

As they worked, the brunet found himself wandering towards the large machine.

The shadow it created engulfed his entire frame.

Leaning forward, Eren rested his forehead on the cold metal and closed his eyes, his left eye missing it's usual eye patch.

He didn't realize he had been like that for quite a while, until he felt his mother's warm hand on his shoulder.

Glancing back, he saw their worried expressions.

Rico had informed Hanji on what happened with the documents, and it must have taken everything within his mother's body as to not go and find Grisha and kill him with her own bare hands.

Eren let his gaze fall on the time machine before meeting his mother's. "I want to be the one you send back in time."

* * *

End of chapter 1. 

**Author's Note:**

> Please, let me know how I did and how I can improve with this idea; comments are much appreciated. 
> 
> And please do me a favor, if it's late at night, turn off your electronic where you're reading and get some sleep, okay? 
> 
> Tumblr- erenlevijeager  
> Discord- Myshka #7185.


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